Systems have been developed in the past for dispensing fluids in a controlled manner. Such systems have included positive displacement systems in which a fluid is suctioned from a container, such as by a pump. For instance, the "Compublend" brand cleaning chemical management system available from the Minnesota Mining and Manufacturing Company Co. of St. Paul, Minn. is an example of one such system. While having its own utility, positive displacement systems generally are expensive and complicated, and may not be desirable for relatively low volume applications.
Another approach is to utilize a venturi effect to suction a fluid from a container. This latter approach also is advantageous in that it is frequently desirable to mix or dilute the fluid with one or more other fluids prior to use. For instance, if the fluid to be dispensed is a cleaning chemical, disinfectant, herbicide or insecticide, it may be desirable to dilute the chemical prior to application with water or another fluid for safety, efficacy, or economical reasons. In such cases, water may be induced to flow past the fluid and the fluid placed in communication with the stream of water. As is known in the art, the velocity of the water creates a lower pressure in the stream that induces the fluid to be siphoned into the stream, simultaneously diluting the fluid. An example of a venturi effect fluid dispensing system is the Hydro Omni-Clean brand proportioning and dispensing system available from the Hydro Systems Company of Cincinnati, Ohio.
However, venturi effect fluid dispensing systems, while having their own utility, are undesirable for many situations in which high levels of accuracy and consistency are desired or required. Typically, conventional venturi affect systems provides an accuracy rate that widely varies from the desired rate. That is, over time, although average rates may be close to what is desired, fluctuations in the flow rate may widely exceed or fall below desired values.
Another type of fluid dispensing system is a gravity feed fluid dispensing system in which a bottle or like container containing a quantity of the fluid is inverted and the fluid allowed to flow downwardly from the bottle under the influence of gravity. An example of a gravity feed fluid dispensing system is the Model S100 brand carbonated beverage dispenser available from SodaMate Enterprises Inc. of Trumbull, Conn. The Model S100 dispenser includes an inverted bottle containing a beverage concentrate and a source of a pressurized carbonated water. The concentrate is mixed with the carbonated pressurized water as a dilutant and then dispensed into a suitable beverage container for consumption. Although the Model S100 dispenser operates effectively with such carbonated beverages, it is not designed for use with non-carbonated fluids. Further, the design requires the use of an external power source, such as compressed carbon dioxide gas. This increases the complexity and cost of the dispenser.